Motion sensing using hall voltage signals

Abstract

An integrated circuit (IC) chip including an array of asymmetrically distributed magnetic field sensing elements. Additionally, an integrated circuit (IC) chip includes a substrate, a sensing coil supported by the substrate and enclosing a portion of substrate, and a Hall effect sensor supported by the portion of the substrate enclosed by the sensing coil.

What is claimed is: 
     
       1. A method comprising:
 vibrating a magnet relative a first coil in response to driving a current through the first coil; 
 concurrently measuring a back electromotive force (bEMF) signal using a second coil affixed to the first coil and a Hall voltage signal using a Hall effect sensor (HES) disposed within the second coil; and 
 determining a velocity of the vibrating magnet by using a sensing matrix and the concurrently measured bEMF signal and Hall voltage signal, 
 wherein an inverse of the sensing matrix maps the concurrently measured bEMF signal and Hall voltage signal to the velocity of the vibrating magnet and a rate of the current driven through the first coil, and 
 wherein the method further comprises determining the rate of the current concurrently with the determining of the velocity. 
 
     
     
       2. The method of  claim 1 , further comprising:
 verifying that the determined rate of the current exceeds a threshold; and 
 adjusting one or more elements of the sensing matrix in response to the verifying. 
 
     
     
       3. The method of  claim 1 , further comprising:
 measuring the current concurrently with the measuring of the bEMF signal and the Hall voltage signal; 
 determining a rate of the measured driving current by differentiating the measured driving current; 
 verifying that the determined rate of the current is different from the rate of the measured driving current by a threshold; and 
 adjusting one or more elements of the sensing matrix in response to the verifying. 
 
     
     
       4. The method of  claim 3 , wherein the adjusting comprises applying a filter on the one or more elements of the sensing matrix. 
     
     
       5. The method of  claim 4 , wherein the applying of a filter comprises performing a running average of the one or more elements of the sensing matrix. 
     
     
       6. A displacement measurement system comprising:
 (i) a haptic engine comprising
 a) a first coil, 
 b) a mass supporting a magnet, the mass being movable relative to the first coil, and 
 c) a hybrid sensor affixed to the first coil, wherein the hybrid sensor comprises 
 (I) a substrate, 
 (II) a second coil disposed on the substrate and enclosing a portion of substrate, and 
 (III) a Hall effect sensor (HES) element disposed on the portion of the substrate enclosed by the second coil; and 
 
 (ii) a digital signal processor (DSP) configured to determine displacements of the mass based on a back electromotive force (bEMF) signal and a Hall voltage signal induced in the second coil and in the HES, respectively, due to magnetic field changes caused by motion of the mass when a driving current is being driven through the first coil. 
 
     
     
       7. The displacement measurement system of  claim 6 , wherein the hybrid sensor is an IC chip. 
     
     
       8. The displacement measurement system of  claim 7 , wherein the hybrid sensor is an ASIC with the DSP formed on the IC chip. 
     
     
       9. The displacement measurement system of  claim 6 , wherein
 the substrate is a PCB board, and 
 the HES is formed on a chip, the chip being connected to a socket of the PCB board disposed on the portion of the PCB board enclosed by the second coil. 
 
     
     
       10. The displacement measurement system of  claim 9  wherein the DSP is disposed on the PCB board. 
     
     
       11. The displacement measurement system of  claim 6 , comprising
 a plurality of the hybrid sensors c) affixed to the first coil, 
 wherein the DSP is configured to determine the displacement of the mass based on the bEMF signal and the Hall voltage signal output by each of the plurality of the hybrid sensors c). 
 
     
     
       12. The displacement measurement system of  claim 11 , wherein the plurality of the hybrid sensors c) forms a 1D array. 
     
     
       13. The displacement measurement system of  claim 11 , wherein the plurality of the hybrid sensors c) forms a 2D array.